molecular relationships in the veronica hederifolia complex (plantaginaceae, veroniceae)

Veronica is a species-rich genus of the plantaginaceae, comprising over 500 annual and perennial herbs distributed across both hemispheres. we examined relationships within the veronica hederifolia complex (v. hederifolia, v. cymbalaria, v. panormitana, and v. triloba), all belonging to v. subg. cochlidiosperma. overlapping morphological features complicate taxonomic delimitation in this group. to clarify species boundaries, we analysed 28 sequences from three regions: the nuclear low-copy cycloidea2 region, the nuclear ribosomal internal transcribed spacer (its), and the plastid dna (trnl–trnf), in addition to morphological characters. morphological variation was observed in leaf shape, calyx and pedicel orientation, corolla diameter and colour, sepal form, and seed features. bayesian phylogenetic inference revealed that the cyc2 marker provided the highest resolution, confirming the monophyly of the complex and distinguishing v. triloba as a separate species. v. cymbalaria and v. panormitana formed sister lineages, with v. panormitana as the earliest-diverging taxon. plastid trnl–trnf sequences showed limited variability, and its data displayed partial incongruence, likely due to hybridization, introgression, and polyploidy. overall, integrating molecular and morphological evidence highlights the utility of low-copy nuclear markers in resolving recently diverged and reticulate lineages, supporting distinct evolutionary trajectories within the v. hederifolia complex. veronica is a species-rich genus of the plantaginaceae, comprising over 500 annual and perennial herbs distributed across both hemispheres. we examined relationships within the veronica hederifolia complex (v. hederifolia, v. cymbalaria, v. panormitana, and v. triloba), all belonging to v. subg. cochlidiosperma. overlapping morphological features complicate taxonomic delimitation in this group. to clarify species boundaries, we analysed 28 sequences from three regions: the nuclear low-copy cycloidea2 region, the nuclear ribosomal internal transcribed spacer (its), and the plastid dna (trnl–trnf), in addition to morphological characters. morphological variation was observed in leaf shape, calyx and pedicel orientation, corolla diameter and colour, sepal form, and seed features. bayesian phylogenetic inference revealed that the cyc2 marker provided the highest resolution, confirming the monophyly of the complex and distinguishing v. triloba as a separate species. v. cymbalaria and v. panormitana formed sister lineages, with v. panormitana as the earliest-diverging taxon. plastid trnl–trnf sequences showed limited variability, and its data displayed partial incongruence, likely due to hybridization, introgression, and polyploidy. overall, integrating molecular and morphological evidence highlights the utility of low-copy nuclear markers in resolving recently diverged and reticulate lineages, supporting distinct evolutionary trajectories within the v. hederifolia complex.